Maximum lying bout duration affects the occurrence of shoulder lesions in sows

Shoulder lesions are caused by tissue breakdown of the skin and/or underlying tissue as a result of long lasting pressure. The lesions are commonly seen in sows during the period of lactation and contribute to poor animal welfare as well as affecting the consumers' attitudes towards the swine industry. The aim of this study was to investigate the correlation between prolonged recumbency during early lactation and development of shoulder lesions, in particular the lying bout time. Eighteen sows of Swedish Landrace were observed for 24 hours during the day of farrowing and day 2, 4, 9 and 11 after farrowing in May 2009. The data were analysed for correlations between the duration of the longest observed uninterrupted lying bout and the prevalence of shoulder lesions recorded at weaning (week 5). In the study, shoulder lesions were observed in eight of the eighteen sows at the time of weaning. The total lying time of the sows was highest on day 0 and day 2, when the proportion of time spent in lateral recumbency over the 24-hour period was on average 80 percent. The longest lying bout had an average duration of 6,3 hours (right side) and 7,2 hours (left side). A significant correlation (Spearman rank coefficient = 0,88; P < 0.05) was found between the duration of the longest observed uninterrupted lying bout and the occurrence of shoulder lesions on right side among well conditioned sows with a low amount of straw present at farrowing. This suggests that avoiding prolonged uninterrupted recumbency contributes to the prevention of shoulder lesions in sows.